Modified differential evolution method for capacitor placement of distribution systems

Optimal capacitor placement determines the size and location of capacitors to be installed on a radial distribution feeder. The capacitor placement problem is a combinatorial optimization problem having an objective function composed of power losses and capacitor installation costs subject to bus voltage constraints that are commonly solved by employing mathematical programming methods. This paper presents a new capacitor placement method which employs modified mixed integer hybrid differential evolution (MIHDE) method and sensitivity factor of buses for a given load pattern of distribution systems. The sensitivity factors help reduce the number of alternatives to be examined and MIHDE finds the optimal solution. The proposed approach is demonstrated by employing an application example. Numerical results show that the proposed method can achieve an optimal solution as the exhaustive search can but with much less computational time. This method is especially beneficial for capacitor placement of large distribution systems.